Alloy



UNITED STATES PATENT OFFICE.

rm A. IAHBENWAIJ), OF CLEVELAND, OHIO.

ALLOY.

80 Drawing.

To a]; whom it may concern:

Be it known that I, FRANK A. Fermen- ALB, a citizen of the United States, residmg at Cleveland, in the county of Cuyahoga and State of Ohio, have invented a certam new and useful Improvement in Alloys, of which the following is a full, clear, and exact description.

This invention relates to alloys of beryllium, and has for its object the production oi alloys of extreme lightness, combined with sufiicient rigidity, tensile strength, and resistance to heat and oxidation for praclical structural and mechanical purposes.

I have found that the alloys of beryllium possess properties more valuable in some ways than those of the similar and better known metals aluminum, magnesium, and calcium, and that certain of the valuable attributes of aluminum and magnesium (and to a smaller extent those of calcium) can be enhanced by the addition of beryllium thereto. Chief among the peculiar attributes of beryllium are its low specific gravity, it low atomic weight, its resistance to oxidation and chemical action, and its ability to form a close grained, impervious adherent oxid which forms an eflicient protection against deterioration of any alloy in which it is contained. B combining this metal with other metals 0 low specific gravity but less immunity to oxidation it is possible to secure a substance of great lightness and permanence; while by the addition of small amounts of certain allied softness and ductillty, but if alloyed with.

certain other metals as herein *pointed out its tensile strength and .hardness'fare in; creased by an amount de ending upon the nature and proportion o the other metal added; which nature and proportion are dependent upon -the use contemplated and upon the value of that use which determines Specification of Letters Patent.

Patented Mar. 16,1920.

Application fled June as, 1917. Serial no. 17am.

to some extent the intrinsic value of the metals which can be employed therein.

For an alloy of extreme lightness I employ lithium and beryllium, the beryllium serving to protect the lithium from oxidation by moisture or heating and further action upon oxidation to produce upon the surface of the alloy a closely-adherent finelytextured, insoluble oxid which prevents further oxidation up to a lithium content of about 25% the corrosion tendency is apparently no greater than that of iron, while the specific gravity of such an alloy is only about 1.5.

If the proportion of lithium be increased to about 65% the alloy becomes as light as Lithium alone is inapplicable to any me:

chanical or structural use owing to its softness and ductility and the fact that it decomposes Water readily. It becomes valuable by reason of the great hardening effect and by reason of the shielding actionof beryllium, both of which results are accomplished with less increase of specific gravity than would be possible with any other metal. The same is true of calcium, which, while normally of great softness and ductility and readily tarnished by moist air, becomes rigid and resistant upon allo ing with beryllium. Besides the alloys 0 beryllium and calcium are extremely light in weight, and added stiffness can be imparted by the addition of a small percentage of copper or zinc or a larger percentage of aluminum.

Thus the alloy of calcium 75% and berylr the hardness and stiffness being far greater than that of pure aluminum. a

v A more important use of beryllium is the hardening of aluminum or ma esium. Calcium has been-proposed for alloym with aluminum for this purpose, but its e ect' is limited by the fact that aluminum will disup to about eigpt 'pel solve calcium onljaecording to L.-

cent. by weight Hum 25% has a maximum hardness combined with a specific gravity of about 1.6,-

onski, I

Z citsc'hm'ft ft'ir An'orgam'sche Ohemz'e, vol. 57 p. 185, 1908, M etallurgie, vol. 7, p. 5 72,1911 which corresponds to only about SIX atomic per cent. and the resulting alloy 1s incapable of bein drawn into wire. Eight per cent. by weig t of beryllium alloyed with ninetytwo per cent. of aluminum corresponds to over twenty atomic 'er cent. of the whole with a corres onding y large effect u on the properties 0 the, resulting alloy. y 1nvestigations indicate a solubility of beryllium. in aluminum even reater than this, with the production of ma leable and ductile alloys.

Alloys of aluminum and beryllium: have approximately the same specific gravity as the corresponding alloys of aluminum and calcium, but with enhanced strength, hardness, and stiffness and greater resistance to corrosion. For example, the specific gravity of an alloy of Al 90, Be 10 is 2.5 and that of an alloy of Al 75, Be 25 is 2.4. Owing to the frequent occurrence together of aluminum and beryllium oxids I anticipate a considerable degree of importance for this alloy.

Furthermore the addition of beryllium to the alloy of aluminum and calcium ap are to increase the. solubllity of the ca c1um therein, rendering the same more tough and 'malleable and less brittle and permitting the hardness to be increased still further,

For a lighter alloy of substantially the same strength I recommend beryllium and magnesium, whose entire series is less than twice the specific gravity of water. These a1 loys also preferab y possess a preponderating amount of magnesium, a composition of Mg 90, Be 10 being of apparently hi h commercial value. This alloy is also su ciently resistant to heat and moisture for most practical pur oses, while further protection can be given by plating or coating.

The addition of beryllium also improves the properties of calcium-magnesium alloys in the same way as alloys of aluminum and calcium. Outside of its beneficial efiect with an extremely low specific gravity.

as a solvent, the berylliumafiords a peculiar advanta e due to the large atomic efi'ect produced by a small weight per cent. coupled alloys with magnesium and copper. or aluminum and copper, the copper being emvariations in solubility occur between these metals, the limit of solubility of zinc bein ticles subjected to high temperatures, since the superficial oxidation of the beryllium will protect the alloy from destructive co'rrosion up to the melting point of the alloy and regardless of the time element. The same protective functionalso appears when beryllium is alloyed with other metals having an atomic weight between 48 and 66 although I consider the copper alloys superior practically to those of the other members of that group. In general the alloys of beryl- 'lium with chromium, manganese, iron, cobalt and nickel, develop a considerable tendency toward segregation as well as a coarsely crystalline structure which reduces their mechanical strength and prevents their being drawn into wire. Copper and zinc afford hardness to beryllium and its alloys with less tendency toward these objectionable qualities, and the beryllium bronzes are more useful than the corresponding aluminum bronzes, being of higher melting point, more resistant to oxidation at high temperatures, and of reater mechanical strength and hardness. lhese bronzes ma contain aluminum, tin, manganese, nicke, etc., for hardening purposes'without destroying the properties bestowed by beryllium. However the proportion of beryllium ought to be either very small or very large, in order to produce a homogeneous alloy,-and the high cost of beryllium practically necessitates the use of the smaller proportion. In.

fact the protective eflect of beryllium upon copper, or other metalsnear copper in the same group, is strongly exhibited even though only two to five per cent. ofthe A metal be present. Beryllium also makes excellent -ternary l havelfound thatthe :metal-lic beryllium is a particularly efiicent carrier of electric current and when produced in the form of drawn ductile wires is extremely useful in the construction of electrical apparatus .where large carrying capacity per .unit of weightis' required; The alloys containing over per cent. of beryllium are more efficient in this respect than copper or alu-.

minum. Wires of these beryllium alloys can be used not only cold but are peculiarly applicable as resistance heating elements owing to their becoming magnesium calcium, beryllium aluminum-' calcium, and berryllium-lithium-aluminum (with or Without the use of small proportions of heavier metals such as copper or zinc for hardening purposes) are of extreme value in aerial navigation, land and water transportation, and the rapidly moving parts of machinery, aswill be obvious.

In preparing alloys of high beryllium content I have employed several methods. The pure element may be melted and the zinc, copper, aluminum, magnesium, lithium, calcium, etc., added directly to the molten bath, or a previously prepared alloy of beryllium and some other metal may be fortified or modified by further additions. Pure beryllium can be produced by the electrolysis of a fused salt in a manner similar to that for aluminum; and similarly by reducing a double salt or ore containing both beryllium and another metal an alloy may be produced directly. This method has been of greatest promise when using natural ores of beryllium, Which usually contain aluminum.

Having thus described my invention, what I claim is:

1. An alloy composed of the metals aluminum and beryllium.

2. An alloy, comprising aluminum and one per cent. to ninety per cent. beryllium.

3. An alloy, comprising beryllium and one or more metals in the class embracing aluminum. a

4:. An alloy possessing greater strength and less Weight than aluminum, comprising aluminum and beryllium the aluminum being in preponderating amount.

5. An alloy which is stronger, harder and of lighter weight than aluminum, consisting of aluminum and less than sixty-five per cent. beryllium.

6. An alloy, composed of one to twenty per cent. beryllium, with the balance chiefly aluminum.

In testimony whereof, I hereunto afiix my signature.

FRANK A. FAHRENWALD. 

